The Causal Relationship Between Obesity and Mechanical Complications of Prosthesis After Arthroplasty: A Mendelian Randomization Study

Abstract Background: Observational studies have identified associations between Obesity and Mechanical Complications of Prosthesis After Arthroplasty. But such studies are susceptible to reverse causation and residual confounding. In addition, there was a lack of randomization control studies to estimate the causal relationship. Here we used Mendelian randomization to assess whether the association might be causal. Methods: In this study, single nucleotide polymorphisms associated with obesity was extracted as instrumental variables from the Gene-Wide Association Study database (GWAS). Data on genetic variants of Mechanical Complications of Prosthesis was obtained from the Finnish database. Heterogeneity of the data was assessed using IVW, MR-Egger and Cochran's Q statistics. Potential causality was assessed using inverse variance weighting, Mendelian randomisation Egger, and weighted median methods. Results: Inverse variance-weighted regression associated Complications of Prosthesis After Arthroplasty with body mass index, waist circumference, and hip circumference (all odds ratios＞1, P＜0.05). Heterogeneity was minimal and no evidence of horizontal pleiotropy was found. Conclusion: Our results enriched findings from previous epidemiology studies and provided evidence from MR that obesity is a risk factor for complications of prosthesis after arthroplasty.